The present invention relates to mosquito repellent compositions comprising an active agent and an oil-soluble, water insoluble acrylate polymer. The compositions are more substantive to human skin and are thus more effective than prior insect repellent compositions.
Over the years, chemical agents such as dimethyl phthalate and N,N-diethyl-m-toluamide (DEET) have been applied to the human skin as insect repellents. They function by vaporizing from the skin. Initially, when there is a large reservoir, evaporation is rapid, which depletes the reservoir and quickly reduces the effectiveness. In addition, the agents can be absorbed directly into the body, rubbed off or washed off by perspiration or water, again depleting the reservoir. In hot and humid weather, the active agent loses its effectiveness even faster. In order to solve these problems, solvents and other chemicals have been incorporated into formulations to improve their effective lifetimes.
U.S. Pat. No. 3,590,118 describes a composition which incorporates known chemical repellents and a water soluble terpolymer resin in a solution which forms a film when applied to skin. The repellent is slowly released to the environment by diffusion and the composition has an effective life longer than that of the repellent agent alone. Effectiveness of up to 24 hours in a temperate climate has been observed. However, the film is stiff which can result in flaking of the film and loss of repellent qualities.
U.S. Pat. No. 4,477,467 describes an insect repellent composition containing DEET as the active agent and an aromatic proton donor as carrier. The carrier can be: (a) monocyclic aromatic with substituted hydroxyl or carbonyl groups or both; and (b) polycyclic aromatic with substituted hydroxyl or carbonyl groups or both. This repellent composition is said to have a longer lasting effect due to increased resistance to absorption through the skin by forming a complex.
U.S. Pat. No. 3,966,902 describes a composition comprising an effective amount of an active ingredient such as a medicinal agent, a disinfectant, a pesticide, an insect repellent or a cosmetic agent in a carrier polymer of a monomer having hydrophilic functional groups containing aluminum, zinc or zirconium bound in complex form. The monomers can be hydroxyl alkyl esters of alpha-beta-unsaturated carboxylic acids (2-hydroxyethylacrylate or methacrylate). These monomers can be reacted with aluminum salts to form complexes.
U.S. Pat. No. 4,304,591 describes a water-insoluble hydrophilic gel comprising a hydrophilic polymer of mono-olefinic monomers cross-linked with a major amount of a diolefinic non-hydrophilic monomer for use as a carrier for medicaments, pesticides, and fragrances for controlled release.
U.S. Pat. No. 4,335,104 describes a multi-purpose anhydrous cosmetic composition which comprises a water insoluble surfactant in combination with active chemical agents. The product has increased and/or prolonged activity in topical applications to skin.
U.S. Pat. No. 4,303,675 describes a mosquito repellent which has a persistent action and is water soluble. The active agent consists of 2,5-dimethyl-2,5-hexanediol and is formulated with an inert carrier in the form of a cream, lotion, spray, soaking agents for towels or a thermal diffusion tabloid.